Catalonia’s deposed president, Carles Puigdemont, has promised to respect the results of December’s snap regional elections and said he would leave Belgium and return home immediately if a fair judicial process were guaranteed in Spain.

Puigdemont, who could face charges of rebellion, sedition and misuse of public funds over his administration’s push for independence, travelled to Brussels hours before Spain’s attorney general announced the possible charges on Monday.

In a possible sign that Madrid has gained the upper hand in the dispute, he told a packed press conference in the Belgian capital that he would abide by the results of the snap regional elections on 21 December, called by the Spanish prime minister, Mariano Rajoy.

Puigdemont said he accepted the challenge of the elections “with all our strength”, dispelling fears that secessionists might boycott the ballot in the hope of denying it legitimacy. Spain wants Catalonia “to abandon our political project, and they won’t achieve it”, he said.

The poll date was set last Friday when Rajoy stepped in to take control of the region and sack Puigdemont and his administration in an attempt to restore legal and constitutional order following the unilateral independence referendum and subsequent declaration of independence in the Catalan parliament.

The ousted leader said he had come to the Belgian capital to seek safety and freedom, and accused Spanish police of failing to protect his rights and those of other separatist leaders.

Speculation that Puigdemont would apply for asylum rose when he appointed Paul Bekaert, a Belgian lawyer specialising in asylum and extradition, on Monday, but Puigdemont ruled out the move when questioned about it by reporters the next day.

Asked how long he would stay, Puigdemont responded: “It depends. I need guarantees.”

Later on Tuesday, a judge at Spain’s top criminal court, the Audiencia Nacional, summoned Puigdemont and 13 members of his former cabinet to testify on Thursday and Friday as part of the investigation into allegations of sedition, rebellion and misuse of public funds.

Shortly before Puigdemont’s press conference, Spain’s constitutional court announced that it was suspending last Friday’s unilateral declaration of independence, while the supreme court said it had begun proceedings against Catalan parliamentary officials over their role in the referendum. Separately, Spain’s civil guard police force searched the headquarters of Catalonia’s regional police.

Puigdemont’s appearance in Brussels, flanked by five of his ousted regional ministers, marked a further twist in the month-long crisis triggered by the 1 October referendum.

It also coincided with a regional poll that showed that support for an independent Catalan republic had risen to an almost three-year high in October, with 48.7% of Catalans believing the region should be independent, up from 41.1% in June.

Q&A

Why does the Spanish government say the Catalan referendum is illegal?

The Spanish government argues that any referendum on Catalan independence would be illegal because the country’s 1978 constitution makes no provision for a vote on self-determination.

A spokesman for the Belgian prime minister, Charles Michel, said Puigdemont had not been invited by the Belgian government. “Mr Puigdemont has the same rights and duties as all European citizens, no more, no less,” the spokesman said.

Earlier in the day, Belgium’s deputy prime minister, Kris Peeters, noted tartly: “If you are going to declare independence, you usually stay with your people.”

Guy Verhofstadt, a former Belgian prime minister, mocked the Catalan separatist leader, when he said internet memes comparing Puigdemont to cartoon detective Tintin were inadequate. “Tintin always finds solutions to the adventures he encounters, while Puigdemont left Catalonia in chaos and devastation.”

Puigdemont’s dramatic arrival in Brussels prompted a slew of internet memes, comparing him to Belgian cultural icons, including Tintin and the Manneken Pis, “the peeing boy” statue in Brussels.

The Catalan drama threatens to be a headache for Belgium’s government, a four-party coalition of Flemish nationalists, liberals and Christian Democrats that came into office in October 2014 after five months of negotiations.

Belgian politicians are worried about damaging relations with Madrid. Some opposition politicians have accused Michel of failing to discipline the immigration minister, Theo Francken, a leading member of the Flemish separatist N-VA party, who appeared to lay down the welcome mat for Puigdemont when he told local media at the weekend: “If the Catalans demand asylum, Belgian law permits it.”

Puigdemont seemed sensitive to the tensions, telling journalists he had had no contact with the N-VA. “This is not a matter of the Belgian politics,” he said. “I am here in Brussels as the capital of Europe.”

The EU has said the Catalan referendum was illegal and that it will only deal with Spain’s central government in Madrid.

Puigdemont blamed Madrid for the impasse, saying the crisis had been sparked by the Spanish police’s heavy-handed attempts to stop the referendum. “The chaos started on 1 October with violence on the Spanish side,” he said.

A Spanish government spokeswoman in Barcelona told reporters that Catalan autonomy had not been suspended, but was “just under new management”.

At a press conference in Barcelona, taking place while Puigdemont was speaking, she said: “We are not here to occupy the administration, but to oversee a return to normality as soon as possible. We intend to have minimal involvement. The transition has been very smooth.”